imagecolormatch

(PHP 4 >= 4.3.0, PHP 5)

imagecolormatch — Makes the colors of the palette version of an image more closely match the true color version

설명

bool imagecolormatch ( resource $image1 , resource $image2 )

Warning

This function is currently not documented; only the argument list is available.

매개변수

image1: A truecolor image link resource
image2: A palette image link resource pointing to an image that has the same size as image1

반환값

성공할 경우 TRUE를, 실패할 경우 FALSE를 반환합니다.

주의

Note: 이 함수는 PHP에 포함된 GD 라이브러리를 사용하여 컴파일하였을 경우에만 사용할 수 있습니다.

Note: 이 함수는 GD 2.0.1 이상이 필요합니다. (2.0.28 이상을 권장합니다)

참고

imagecreatetruecolor()

add a note User Contributed Notes
imagecolormatch

albriNOght at anSPAMre dot net
12-Dec-2005 09:22


This function appears to work by changing the values of the colors of the paletted image -- no good if you're trying to force the resultant image to stick with certain pre-defined color values.

Samantha
08-Feb-2004 07:14


This function is a godsend! It works exactly as documented.



I'm working on an application where I need to take a transparent GIF, matte the GIF on a user defined background color, and finally scale the GIF based on a user defined %.



The only way I could get this to work so that the final image was high quality, ie: no jagged edges, and a smooth scale, was to convert the GIF to a JPG, and then copy the JPG into a new GIF image like this:



// open transparent gif

$GIFimg = imagecreatefromgif($file_path);



// create jpg image

$JPGimg = imagecreatetruecolor($width, $height);



// copy GIF to JPG

imagecopy($JPGimg, $GIFimg, 0, 0, 0, 0, $width, $height); 



// create a true color image

$JPGscaled = imagecreatetruecolor($n_width, $n_height);



// scale the new JPG using the truecolor image

imagecopyresampled($JPGscaled, $JPGimg, 0, 0, 0, 0, $new_width, $new_height, $width, $height);



// create final GIF image

$GIFfinal = imagecreate($n_width, $n_height);



// copy the scaled JPG back to a GIF

imagecopymerge($GIFfinal, $JPGscaled, 0, 0, 0, 0, $n_width, $n_height, 100);



This worked great except the final step, copying the JPG to a GIF. If the JPG had too many colors, the function would index the colors to make it a palette image. So what would end up happening is the final image contained INCORRECT colors.



Adding this one line at the bottom of the code fixed everything.



imagecolormatch($JPGscaled, $GIFfinal);



I hope this helps anyone who is converting images back and forth and dealing with palette issues and color correction. Also, be aware that the above code is a sample and will not work by copying and pasting.

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imagecolorresolve

imagecolorexactalpha

Last updated: Sun, 25 Nov 2007